First, see whether the logo is complete. Authentic products of good quality packaging, the box on the clear handwriting, overprinter color. The packing box, the bag, the be has the product name, the specification type, the quantity, the registered trademark, the Factory plant address and the telephone number and so on, some manufacturers also in the accessories to play own mark. Some important components such as generators, distributors, fuel injection pumps, etc., but also with the use of manuals, certificates and inspectors chapter, to guide users to correct use of maintenance. Purchase should be carefully recognized in order to prevent the purchase of counterfeit products.
Second, see if the geometrical size is deformed. Some parts due to manufacturing, transportation, storage improper, easy to produce deformation. Inspection, the shaft parts can be rolled along the glass plate, see if the parts and the glass panel light to determine whether or not to bend; Choose the clutch from the moving plate steel or friction film, can be steel, the friction sheet is raised in front of the eye to see if it is warping; When choosing oil seal, the end face of the oil seal with skeleton should be round, can be fitted with the flat glass without flexing, and the outer rim of the oil seal without skeleton should be correct, with hands to make it deformed. In the selection of various types of liner, you should also pay attention to check the geometrical size and shape.
Third, see whether the binding site formation. Spare parts in handling, storage process, due to vibration, bump, often in the joint site produced Burr, indentation, breakage or cracks, affecting the use of parts. Pay attention to check when purchasing.
Four, see if the surface of the parts rust. Qualified parts of the surface, both a certain degree of precision and polished finish, the more important parts, the higher the precision, the more stringent anti-rust anti-corrosion packaging. When purchasing, should pay attention to check, if found parts have rust spots, mildew spots or rubber pieces cracked, lose elasticity, or the axle neck surface has obvious vehicle blade lines, should be replaced.
Five, see whether the protective surface is intact. Most parts are coated with protective layers at the factory. such as piston pins, bearings with paraffin protection, piston ring, cylinder liner coated with antirust oil and wrapping paper, valve, piston and other oil after the dip in plastic bag packaging. If you find that the seal sleeve is damaged, the wrapping paper is lost, rust oil or paraffin wax is lost, it should be returned.
VI. See if the adhesive parts are loose. The parts which are synthesized by two or more parts of more than two components, which are pressed, adhesive or welded, are not allowed to be loosened between them, such as pump plunger and adjusting arm are assembled by pressing; clutch from the wheel and the steel plate is riveted combination, friction sheet and steel plate is riveting or bonding; Paper filter cartridge skeleton and filter is made of adhesive; electrical equipment threads are welded. When the purchase is found loose, should be replaced.
VII. See if the rotational parts are flexible. To buy oil pump, such as rotating parts assembly, with the hand to rotate the pump shaft, should feel flexible without card lag; When choosing rolling bearing, one hand supports bearing inner ring, the other hand circles outer ring, the outer ring should be able to rotate quickly and easily, then stop turn gradually. If the rotation of the parts is not the spirit of the internal corrosion or deformation, do not buy.
Eight, see the assembly parts have an intact. Regular assembly parts must be complete and intact to ensure smooth assembly and normal operation. Some parts of the assembly parts if the leakage of individual components, will make the assembly parts can not work or even scrap.